Fluid blast circuit breaker



Feb. 1, 1944. w. E. PAUL FLUID BLAST CIRCUIT BREAKER S SheetS-Sheet 1 Original Filed Nov. 3, 1938 @KZJMMQLL mmm wwmnio/ A Inventor: -Williarn E.Pau\, 7/ MMZM HIS Attorney Feb. 1, 1944. w 5, U Re. 22,430

FLUID BLAST CIRCUIT BREAKER Original Filed Nov. 3, 1938 3 Sheets-Sheet 2 William E.Paul,

His AttOrne-g.

Feb. 1, 1944. w. E. PAUL FLUID BLAST CIRCUIT BREAKER Original Filed Nov. 3, 1938 3 Sheets-Sheet 25 Fig. 5.

h wvefitor: William E. Paul, j'v a/wycffx wafi/w His A ht ornay.

Ra... rat. 1', 1944 V 22.430 ram mas-r cracurr BREAKER wuum s. rm. Schenectady, N.

General Electric Company, a

I New York Original No.

No. 238,632, reissue August My invention relates to fluid blast circuit breakers, and more-particularly to gas blast cir-- cuit breakers wherein a source of pressure, independent of the magnitude of the current to be interrupted, is utilized to elfect arc interruption.

The principal object of my invention is the provision oi an improved fluid blast circuit breaker that has high interrupting capacity and that is eiiicient and positive in operation throughout the entire rating of the circuit breaker.

More particularly, a further object of my invention is the provision of means in a fluid blast circuit breaker for segregating or isolating metallic vapor formed by the are at 'the coacting contact surfaces so that the portion of the arc path subject to the fluid blast, is substantially free of said metallic vapor.

A further object of my invention is the provision in a fluid blast circuit breaker oi improved blast producing means including a supplemental source of stored energy for supplementing and sustaining the fluid blast at the arc.

A further object of my invention is the provision of an improved operating means in a fluid blast circuit breaker of the character above defined for relating the contact structure to pneumatic operating means,

My invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawings, Fig. 1 is an elevational view, partly in section and partly diagrammatically shown, of a fluid blast circuit breaker in the open circuit position thereofv embodying the present invention, Fig. 2 is a. similar view showing the circuit breaker in the closed circuit p sition, and Fig. 3 is a modified form of my invention illustrating a double-break type gas blast breaker.

The fluid blast circuit breaker specifically illustrated by Figs. 1 and 2 comprises a pair of relatively movable contacts I and 2 operable within anjiinsulating casing! which forms a blast passage 4 for directing flow of gas through and transversely of the arc path upon separation" of the contacts. The insulating casing 4 also includes.

an arc chute 5 having so-called insulating arc splitters 6 into which the arc is blown'by the transverse blast.

' er contacts shown by Fig. 1.

Y., assignor to corporation of 2,284,940, dated June 2, 1942, Serial November 3, 1938. Application for 19, 1942, Serial No. 455,352

10 Clalms. ((11-200-148) is, asthe arc current increases, the blast pressure must be sufllcient to overcome this are resistance or back pressure so as to permit high velocity gas flow through the arc path, particularly when the alternating current passes through the zero value.

Heretofore the principal method of overcoming the arc resistance or back pressure consisted in utilizing comparatively high source pressures or in splitting the are into a number of sections, all of which are subjected to a fluid blast.

I have found that this arc back pressure can be reduced, and the gas blast made more effective by segregating or isolating the metallic vapor that is evolved from the coacting contact surfaces by the are heat so that this vapor is not present-to any appreciable extent in that part of the arc path subject to the gas blast. By so segregating or isolating the metallic vapor, the arc path is also rendered less conducting, thereby further facilitating arc interruption by the blast at a current zero.

To this end the insulatingcasing 3, preferably at both side of the blast passage 4, is provided with recesses or pockets 1 an 8 within which .both terminals or extremities of the arc path are located in the separated position of the break- Since the contact material vaporized by the are at one terminal at least is always wholly within one or said pockets. itwill be apparent that the metallic vapor in the arc path can be limited to a very small amount.

As specifically illustrated, the contact -.I is substantially fixed and has a limited movement or wipe at the resilient mounting 9. The movable rod contact 2 is guided for reciprocal movement In this form of circuit breaker, it has been found that a heavy current are has a certain resistance to transverse movement that tends to diminish the effectiveness of the gas blast. That in the casing 3 and is operable across the blast passage 4 to engage the fixed contact I. The

. contact 2 is normally biased by a spring It towards open circuit position, and in the closed .circuit, position, referring to Fig. 2, engages the contact within the pocket I. Accordingly, when the breaker is opened, the arc is initially formed in the pocket land is-drawn entirely across the blast passage 4 to the opposite pocket 9.

In view of the fact that an arc, so far as is known, does not actually transport matter such as metallic vapor from one point to another, the metallic vapor evolved at the butt-contact surfaces of l and 2 is not carried into the blast passage 4 except during the very brief interval during which the contact 2 moves across th passage. Accordingly, the metallic vapor is substantially segregated or isolated at the arc terminals or roots with respect to the gas blast intermediate to the crank from th pockets in any suitable way, as through opposite ends of the arc chute I.

It will be noted that the blast passage extending transversely of the intermediate portion of the arc path i or diver ing shape so that the blast has high velocityat the intermediate portion of the are opposite the arc splitters. The effectiveness of the gas blast is further increased by designing the blast passage so that the maximum gas velocity is at the entrance to the arc splitters, as contrasted with the usual method herein the maximum velocity is at the point where the arc is formed. By restricting the blast at the approach to the arc and by 10- cating the splitters in the diver ing part immediately beyond the arc, the blast is made most eii'ective at that point.

15 functions both as an The operating means for the switch contacts comprises in the present instance an operatin rod ii that is related through tripping means, generally indicated at II, to a piston II. when the disengageable tripping device It releases the rod II with respect to the p ston II, the contact biasing spring Ill moves the contact 2 toward the open circuit position indicated in Fig.. 1. The circuit closing operation can be eiiected when the tripping device I! is reset, as illustrated, by admitting gas under pressure to the piston cylinas by means of a manually controlled valve IS. The piston I! in moving toward the opposite end of the cylinder also compresses a spring it in addition to the circuit closing Operation on the contact 2.

Referring more specifically to the tripping device I! a crank I! having a fixed pivot at I! is connected at I! to the piston rod extension 20. The crank I! also has connected thereto a trippi m magnet II and a coacting armature 22. As best illustrated by Fig. 2, the magnet and its armature are copivotally mounted on the crank at 23. The magnet II is also connected at 24 for limited movement with respect thereto. The magnet and crank are normally biased in opposite directions as shown.

A latch 28, copivotally mounted with respect to the armature 22 at 23, is provided with a roller II adapted to engage the end of the switch operating rod I I. The latch 25 is also mounted at 21 for limited movement with respect to the magnet 2| and is resiliently biased toward latching position. The armature 22 has a lost-motion connection, such as a pin and slot connection indicated at 28, with latch II so as to deliver'a hammer blow to the latch in response to a tripping impulse.

When the device is in the closed circuit position, shown by Fig. 2, suitable energization oi the magnet coil II, in a manner hereinafter described, causes counterclockwise movementoi' the trip the latch switch to the open circuit position previously described. I

- Referring particularly to Fig.

closing operation is initiated by opening in any suitable manner the valve it which connects the cylinder II with a source of gas position shown, cylinder I is pressure. Inthe 1, the circuit go former II can be related 28 time delay relay I2 for $0 exhaust valve 33 88,480 portion of the arc. The metallic vapor is vented latch II, after limited movement of the crank I7, must rotate with said crank by reason of the lostmotion connections at 24 and 21.

When the piston stroke is completed, the apparatus is in the position shown by Fig. 2 wherein it is held against the bias of springs i0 and I! by the gas pressure from the line 28. Accordingly, in the closed position the cylinder 14 is prevented by the piston seating as a valve at II.

expansible reservoir for storing gas under pressure and as contact operating means.

For opening the breaker, as in response to an overload or short circuit, the usual current transto suitable tripping relays for initiating both the gas blast and the circuit opening operation. Asshown, the current actuating the tripping device II. The purpose of relay 32 is to synchronize the contact opening with the gas blast.

The relay 3| is operated instantaneously in response to a tripp ng impulse at III to open the for releasing the, pressure at the lower side of the blast valve V. Normally the pressure is equalized on both sides or the bleed vent 34 and the valve the H. The relay energizing circuit of the coil 2| at 32' after a predetermined delay to trip the breaker in the manner above described.

Coincident with blast at the In view of the is generally interrupted within a very few cycles. it will be apparent that the piston II is eii'ective to maintain the blast at high velocity for a sumcient interruption period.

It will be noted that the contact ope movement is independent of the speed of the re-.

turn. stroke of the piston. with this arrangement the stored energy imparted to the piston the crank I! in a 76 reaches the end of its stroke, as shown in Fig. 1.

The cylinder I. therefore is introduced ient connection at when the contacts device ll is rotafid clockwile dur-. strokeoithepistonandtheresil- 21 serves to bias the latch ing thereturn Itwillbenotedthatthe cacao .crecpage'pathtorpreventing restr'ikingoithe are at high voltages. Another important advanmechanism is trip-free" near the end of the closing stroke since the latch 2| can be actuated'by the magnet The control means for the valve II can be of any suitable type and is shown as manually operated for purposes oi 'ous, however,

II to release the contact at this part or the stroke.

. tags is that the loop in the circuit at the arc chambers causes the magnetic iorces to be uti- 'liaedsoastoassistthegasblastindrivingthe arcs into the arc splitters. Thatis, the magnetic forces set up by the current tobe interrupted tend to drive the arcs into the arc splitters independently of the gas blast so that the latter thereby can be even more effective.

In operation it will be noted that the lost motion resilient connections'at 41 between the 918- ton 48 and the bridging contact 4! permits an in- 1 itially high acceleration independently or the and M make butt contact engagement with the and are resiliently mounted at ll and 44', respectively, on the bridging member for limited overtravel or wipe. The bridging member is operated by a. pair of insulating rods 45 that are operatively connected to a piston 46 through a resilient connection 41. The piston 46 in turn is connected to an operating rod 48 guided with respect to the piston cylinder 49. The operating rod can be connected to suitable actuating mechanism (not shown). It will, therefore, be noted that the arrangement is such that opening movement of the contacts through the operating rod 0 also is accompanied by movement of the piston 40 in a direction to direct a gas blast in the direction of the contacts.

For the purpose of directing the gas blast effectively into the arc paths formed between the separating contacts, the piston cylinder 49 is adapted to communicate with an arcing cham her and chute structure generally indicated at ill. The are chute includes a pair of insulating arc chambers iii and l! separated in the present instance by an insulating partition 53. Each chamber is arranged to be in communication with the cylinder 49 through passages 5| and 52' respectively. The contacts I: and 44 in opening pass through the chambers 5i and 52, respectively, and a plurality of arc splitters 54 are disposed in the chute transversely of the arc path at the opposite open sides of the arc chambers. The are gases are therefore directed in opposite directions from the two breaks so that the danget of flash-over, where high voltages are involved, is

For the purpose of segregating the metallic vapor formed by the arc, the arcing chambers 5i and 52 are arranged so that both terminals of the arc can be exteriorly oi the arc chambers, and hence removed from the main gas blast, are in the separated position shown. To this end the chambers overhang, in vertical. spaced relation, the fixed contacts so as to form pockets 55 and 56 for segregating the metallic vapor at the points oi initial arc formation. As illustrated, the metallic vapor is vented at opposite sides of the arc chute and does not enter the arc path. In the same manner the metallic vapor at the contacts 43 and 44 can be vented through the upper open end of the chute.

An advantage oi the present arrangement is that the double break, in combination with the arc splitters; provides a comparatively long bridging contact so that there'is present an efiective gas blast at the instant of contact separation. Aiter predetermined travel of the piston 48, the contact rods 45 are directly engaged to insure positive separation of the contacts. This contact opening speed is very high since the movable contact structure is automatically picked up and accelerated by the inertia of the piston and operating mechanism which are at this point moving at high speed.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent 01 the United States is:

1. An electric air circuit breaker of the cross blast type comprising relatively movable contacts, independent pressure mean-s for directing a. fluid blast transversely through the arc path formed upon separation of said contacts, and means for segregating and dissipating metallic vapor formed by the are at each contact surface at the opposite extremities of the arc path, said metallic vapor being dissipated in directions away from said are path so that the intermediate part of the arc path subject to said fluid blast is substantially free of said vapor.

2. An electric air circuit breaker of the cross blast type comprising a pair of relatively movable contacts, an independent source of fluid pressure, insulating means forming a fluid passage from said source extending transversely oi the arc path formed upon separation of said contacts, said insulating means forming pockets at opposite sides of said fluid passage and separate therefrom, and means for effecting separation of said contacts so that the extremities of the arc path are located substantially within said pockets, said pockets being vented independently of said fluid passages.

3. An electric air circuit breaker of the cross blast type comprising a pair of relatively movable contacts, means forming a fluid passage for directing under pressure a fiuid blast substantially transversely of and through an Intermediate section of the arc path formed upon separation of said contacts, and insulating barrier means disposed adjacent each side of the said segregating metallic vapor formed at the corre-.

sponding contact surfaces, said insulating barrier means defining passages for venting said metallic vapor to atmosphere independently of the arc path.

4. An electric circuit breaker of the gas blast type com-prising relatively movable contacts,

means for separating said contacts, passage spring charging operation on tacts and piston whereby means for directing a gas blast through the arc path "formed upon contact separation, source oi pressure for said gas blast. and a second supplementary source of blast energy including a spring under tension by the pressure from said first source, said main and supplementary sources both communicating with said passage means for interrupting the arc.

5. An electric circuit breaker oi. the gas blast type comprising relatively movable contacts, means for separating said contacts, means for directing a gas blast through the arc path formed upon contact separation, a source 01' presblast. a blast valve for conof gas from said source directly to said contacts, and a second supplementary source of blast energy including an expansible reservoir arranged normally to be under pressure from said first source, said valve also ing the blast from said first source.

6. An electric circuit breaker or the gas blast type comprising relatively movable contacts, a fluid passage for directing a gas blast through the arc path formed by contact separation, a source of pressure for said gas blast, ablast controlling valve directly interposed with respect to said source and passage, a cylinder having a spring biased piston arranged to be in communication with said source in the closed position of said contacts independently of said blast valve whereby said piston is biased to a spring charging position, said valve also interposed with passage for interrupting the are upon separation of said contacts.

7. An electric circuit breaker of the gas blast type comprising relatively movable contacts, means for directing a gas blast through the arc path formed upon contact separation, a source of blast energy comprising a spring charged piston, and tripping means for relating said piston to said contacts whereby circuit closing movement thereof, is effected coincident with the said piston, said to release said conindependent movement of each is permitted during the circuit opening operation.

8. A gas blast circuit breaker comprising separable contacts arranged to form two breaks tripping means being effective arranged normally to be held.

cacao in series. insulating which said breaks pressure into said chain ration of said contacts said splitters. and means tacts ber means upon sepato interrupt arcing at for operating said consulating means, said confining means openin in opposite directions corresponding to the diexhaust openings, and means for directing gas under pressure into said confining means to drive said arcs into said are splitters in accordance with the contact opening operation.

10. A gas blast circuit breaker comprising an insulating arc chute having a comparatively narrow entrance portion and a flared exhaust portion, relatively movable contacts separable at said entrance .portio means defining a fluid passage for directing a gas blast into said chute at said entrance portion and transversely of the are path formed upon separation of said contacts, and a plurality of insulating arc splitters disposed in said chute and extending edgewise in spaced flaring relation from points adjacent WILLIAM E. PAUL. 

